Lecture Notes Flashcards

Chapter 15 & 16 Overview

• Chapter 15 review and Chapter 16 introduction to special senses (ears and eyes).
• Worksheets will be assigned after Chapter 15.
• Blueprint for the final exam will be released this week, providing a week for review.

Important Dates

• Next week (Week 14): Eyeball dissections.
• Homework Due: Assignments for chapters 13, 14, 15, and 16 must be completed before the final exam.
• Grades Finalized: Beginning of Week 16, no extra time for late submissions.

Somatic vs. Autonomic Nervous Systems

• Autonomic Nervous System:
  • Purpose: Homeostasis.
  • Two divisions:
    • Parasympathetic: Rest and digest.
    • Sympathetic: Fight or flight.

Sympathetic Nervous System (Fight or Flight)

• Activated during stress, embarrassment, exercise, or fighting.
• Effects:
  • Whole body activation.
  • Increased heart rate.
  • Adrenaline release.

Parasympathetic Nervous System (Rest and Digest)

• Activated during rest and calm states.
• Effects:
  • Conserves energy.
  • Promotes nutrient absorption.
  • Increased urination and defecation.
  • Targets specific organs.

Pharmacology

• Understanding autonomic functions is crucial in pharmacology.
• Key drug types:
  • Anticholinergics.
  • Cholinergics.
  • Adrenergic.

Ganglia

• Cell bodies outside the CNS (Central Nervous System).
• Types:
  • Preganglionic neurons/axons.
  • Postganglionic neurons/axons.

Axon Length

• Parasympathetic:
  • Long preganglionic axons.
  • Short postganglionic axons.
• Sympathetic:
  • Short preganglionic axons.
  • Long postganglionic axons.

Axon Branching

• Parasympathetic:
  • Preganglionic axons have few branches.
  • Signals sent directly to one effector for a specific job.
• Sympathetic:
  • Preganglionic axons have many branches.
  • Rapidly signals the whole body.

Impact on Medications

• Sympathetic medications affect the entire body.
  • Example: Adrenaline shots.
• Parasympathetic medications can target specific organs (e.g., urinary system).

Sympathetic Trunks

• Location: Immediately lateral to the vertebral column.
• Structure: Two columns along the spinal cord (left and right).
• Composition: Somas of ganglionic neurons; looks like a string of pearls during dissection.

Sympathetic Nerve Pathways

• Preganglionic neurons synapse with ganglionic neurons in sympathetic trunk ganglion.

Gray Rami

• Composed of gray matter (cell bodies/somas).
• Located inside the spinal cord.
• Postganglionic axon may or may not leave the trunk via gray rami.

Spinal Cord Structure

• Cross-section:
  • Sensory nerves in the back.
  • Motor nerves in the front.
  • Interneurons in the middle.
  • Mickey Mouse ears-like structure.
  • White matter tracts and gray matter tracts.

Postganglionic Sympathetic Nerve Pathway

• Everything after the ganglia.

Adrenal Medulla Pathway

• Exception to typical sympathetic pathways.
• Involves only a preganglionic axon going straight to the effector (adrenal medulla).
• Directly stimulates the adrenal gland to release hormones (e.g., adrenaline).

Cranial Nerves

• Vagus Nerve: Supplies parasympathetic innervation to thoracic organs and some abdominal organs.

Nerve Plexuses

• Nerves grow with roots that cross each other.
• Major plexuses:
  • Brachial.
  • Lumbar
  • Sacral (sciatic nerve).
  • Cervical.
  • Thoracic.

Solar Plexus (Cardiac Plexus)

• A gathering and rebranching of nerves that supply both the heart and lungs.
• Targeted point to stun the nerves.
• Compression can cause heart to stop or skip a beat and difficulty breathing.
• Location: Approximately two inches below the collarbones.

Purpose of Plexuses

• Provide multiple pathways for nerve signals.
• If one pathway is compressed or blocked, others can still transmit signals.

Dual Innervation

• Organs receive input from both sympathetic and parasympathetic divisions.
• Example: Heart and lungs.

Antagonistic Effects

• Sympathetic and parasympathetic nerves have opposite effects.
• Example: Heart rate (sympathetic raises, parasympathetic lowers).
• Agonist and antagonist drugs: Raise or block systems, respectively.

Cholinergic and Adrenergic

• Cholinergic drugs: Affect the parasympathetic system (acetylcholine).
• Adrenergic drugs: Affect the sympathetic system.